Overall, fuel economy ratings remained down 0.2 mpg from a peak of 25.5 mpg in August 2014 and up 5.2 mpg from a low of 20.1 mpg recorded when monitoring began in October 2007.

The University of Michigan Eco-Driving Index (EDI) was 0.85 in March, up 0.01 from February. The index estimates the average amount of greenhouse gas emissions generated by U.S. drivers on a monthly basis.

Taking into consideration a combination of fuel economy and driving distance, the EDI value indicates that on average, new-vehicle drivers produced 15% lower emissions in December compared to October 2007, but 7% more than a record low last reached in November 2013.